Dans le contexte énergétique actuel, la conception de panneaux photovoltaïques efficaces représente une des solutions pour pallier à la pénurie prochaine des énergies fossiles. Cependant, les phénomènes de dégradation de l’encapsulant, un des matériaux passifs du panneau, sont une des origines de la baisse de rendement des modules. L’objectif de ce travail de thèse a été de concevoir, caractériser et évaluer les différentes propriétés de nouveaux encapsulants hybrides organique-inorganique contenant des ressources renouvelables. Ainsi, trois matériaux ont été élaborés à partir d’alcool polyvinylique (PVA), de résines terpéniques et de charges minérales (silice ou argile (Bentonite)). Un premier matériau comprenant PVA, résine et silicates, dans lequel composantes organique et inorganique sont liées par des liaisons covalentes fortes (hybride de classe II), a conduit à des stabilités thermiques et photochimiques, et des propriétés optiques et barrières à la vapeur d’eau et à l’oxygène, similaires à celles des encapsulants actuels.L’introduction de nanoparticules de silice dans un mélange PVA/résine via des liaisons faibles a ensuite fourni un matériau hybride de classe I aux propriétés barrières à la vapeur d’eau satisfaisantes mais avec des transparences optiques insuffisantes pour une utilisation comme encapsulant, du fait de l’agrégation des nanoparticules. Enfin, malgré une transparence optique devant être encore optimisée, un matériau hybride de classe I constitué de PVA, de résine et de Bentonite a conduit à de bonnes propriétés thermiques, photochimiques, barrières à la vapeur d’eau et surtout d’excellentes propriétés barrières à l’oxygène, ce qui ouvre de nouvelles perspectives (emballage alimentaire…). / In the current energetic context, the design of efficient solar photovoltaic panels represents one of the solutions to overcome the coming fossil fuels shortage. However, degradation phenomena of the encapsulant, one of the passive materials of the panel, have been evidenced as one of the reasons of the performance decrease. The aim of this PhD research work was to design, characterize and assess the different properties of more environment-friendly new hybrid organic-inorganic encapsulants. In this way, three materials have been developed using polyvinyl alcohol (PVA), terpenic resins and mineral fillers (silica or clay(Bentonite)). A first material including PVA, resin and silicates, in which both organic and inorganic networksare linked through strong covalent bonds (class II hybrid material), led to thermal and photochemical stabilities, and water vapor and oxygen barriers properties similar to those of commercial encapsulants.Dispersion of silica nanoparticles into PVA/terpenic resin mixture through weak bond then provided a class Ihybrid material showing rather good water vapor barrier properties but optical transmittance too low to beused as an encapsulant, due to the aggregation of the nanoparticles. Finally, despite an optical transparency that should be optimized, a class I hybrid material made of PVA, resin and Bentonite showed promisingbehavior with good thermal, photochemical and water barrier properties and remarkable oxygen barrier properties, which opens up new prospects in the field of food packaging.

Im Rahmen des Transferprojektes T01 „Textilbeschichtung mit hochviskosen Massen“ des Sonderforschungsbereiches 532 (SFB 532) wird die Realisierung und Bewertung eines integrierten Beschichtungskonzeptes zur nachhaltigen Verbesserung der Tragfähigkeit von textilbewehrten Betonbauteilen an der RWTH Aachen University untersucht. Dazu wird eine neue Auftragstechnik für hochviskose Beschichtungsmassen entwickelt, die eine vollständige Penetration von Multifilamentgarnen mit großen Garntitern und einer hohen Anzahl an Filamenten in textilen Gelegen erzielt. Des Weiteren werden aktive Beschichtungsmassen auf der Basis von Polyvinylalkohol-Zement-Compositen, die eine homogene Anbindung aller Einzelfilamente an die Zementmatrix ermöglichen, erforscht.

This work seeks to fabricate, optimize, and characterize nanofibers of cactus Opuntia ficus-indica mucilage and Poly (vinyl alcohol) (PVA) by electrospinning. Mucilage is a neutral mixture of sugars produced by cactus and PVA is a non-toxic, water-soluble, synthetic polymer, which is widely used as a co-spinning agent for polymers. Mucilage was extracted from the cactus pad and prepared for electrospinning by mixing with acetic acid. Two types of PVA were used differentiating in high and low molecular weights. Concentrations of PVA were varied to find an adequate threshold for fiber formation. Changing the ratio of PVA to cactus mucilage produced fibers of different diameter and quality. The optimizations of the parameters used in the electrospinning setup were also a factor in creating quality fibers without deformity. An acceptable PVA to mucilage ratio mixture was reached for the use of the electrospinning process and consistent nanofibers were accomplished with the use of both the low and high molecular weight PVA. The fibers were observed using a Scanning Electron Microscope, Atomic Force Microscopy, and Differential Scanning Calorimetry. In this project we were able to obtain nanofiber meshes made with environmentally friendly materials with fiber diameters raging from 50nm to 7um sized. The produced nanofibers were made in the hope that it can be utilized in the future as an inexpensive, biocompatible, and biodegradable water filtration system.

Made available in DSpace on 2014-10-09T12:42:03Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:42Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:42:03Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:42Z (GMT). No. of bitstreams: 0 / Detectores de sulfato de cálcio ativado com cério IV e európio III utilizando o politetrafluoretileno (PTFE, Teflon®) free-flow como aglutinante (CaSO4:Ce,Eu + Teflon®) foram produzidos pelo método da estampagem, desenvolvido em colaboração com a empresa Tecnoflon, a partir de cristais crescidos de acordo com uma nova variação da rota da evaporação lenta, também apresentada nesse trabalho, com as concentrações de 0,16 mol% de Eu3+ e de 0,15 mol% de Ce4+ na solução ácida precursora. O modelo de dosímetro pessoal desenvolvido consiste em cinco detectores aderidos a um cartão de 30 x 48 mm de cloreto de polivinila (PVC) 95% opaco à luz na faixa do espectro eletromagnético que vai do infravermelho ao ultravioleta, idêntico aos cartões de identificação utilizados no IPEN, por uma tira de 10 x 35 mm de filme adesivo do mesmo material e foi submetido aos testes de aceitação descritos no regulamento técnico IRD-RT Nº 002.01/95, Desempenho de Sistemas de Monitoração Individual Critérios e Condições, sendo aprovado em todos os testes. Para a dosimetria clínica, os próprios detectores foram considerados dosímetros termoluminescentes e submetidos aos testes de aceitação descritos no código de práticas da Agência Internacional de Energia Atômica Technical Report Series Nº 398, Absorbed Dose Determination in External Beam Radiotherapy: An International Code of Practice for Dosimetry based on Standards of Absorbed Dose to Water, [TRS-398, IAEA, 2000] adotado como protocolo de dosimetria pela maioria dos hospitais, sendo igualmente aprovados nesses testes. Os dosímetros desenvolvidos podem ser utilizados para a monitoração individual externa e para dosimetria clínica, apresentando a diferenciação do tipo e da energia da radiação com que foram irradiados e a redução de custos como as principais vantagens em relação aos dosímetros termoluminescentes atualmente utilizados nessas aplicações. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2016-04-05T18:07:42Z No. of bitstreams: 2 dissertacao - Leandro Rodrigues da Silva Souza - 2015.pdf: 16210462 bytes, checksum: 475bed9248c2dcb7bf0346adfc69a5f0 (MD5) license_rdf: 19874 bytes, checksum: 38cb62ef53e6f513db2fb7e337df6485 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-04-06T12:44:50Z (GMT) No. of bitstreams: 2 dissertacao - Leandro Rodrigues da Silva Souza - 2015.pdf: 16210462 bytes, checksum: 475bed9248c2dcb7bf0346adfc69a5f0 (MD5) license_rdf: 19874 bytes, checksum: 38cb62ef53e6f513db2fb7e337df6485 (MD5) / Made available in DSpace on 2016-04-06T12:44:50Z (GMT). No. of bitstreams: 2 dissertacao - Leandro Rodrigues da Silva Souza - 2015.pdf: 16210462 bytes, checksum: 475bed9248c2dcb7bf0346adfc69a5f0 (MD5) license_rdf: 19874 bytes, checksum: 38cb62ef53e6f513db2fb7e337df6485 (MD5) Previous issue date: 2015-02-20 / In order to collaborate with technology and accessibility, this work proposes the development of a Space Frame chassis, constructed with polyvinyl Chloride (PVC). To the development were used PVC tubes and fittings, commonly used in civil builders. The essential parameters of the PVC were obtained experimentally and used to simulate the chassis. Along the development, analyses of tension and deformation were made in the proposed structure. Using computer simulation, the finite element analysis could provide the structure behaviour in different scenarios, as bending, tension and deformation. / Com o intuito de colaborar com o campo da tecnologia e acessibilidade, este trabalho propõe o desenvolvimento de uma estrutura veicular do tipo Space Frame, construída a partir de tubos de policloreto de Vinila (PVC). Para tanto, foram utilizados tubos e conexões de PVC normalmente empregados na construção civil. Os parâmetros essenciais do PVC para a simulação foram obtidos experimentalmente. São realizadas análises de tensões e deformações da estrutura, por meio de simulação computacional, utilizando um solver de Elementos Finitos, propiciando análise do protótipo, sob condições de solicitação a flexão devido a cargas distribuídas sobre as suas regiões.

Made available in DSpace on 2014-08-20T14:38:04Z (GMT). No. of bitstreams: 1 dissertacao_mariana_tillmann.pdf: 1164818 bytes, checksum: 36d068fbc96d4569dd3f8db7e6b7f838 (MD5) Previous issue date: 2011-02-21 / The healing process comprises a dynamic cellular process that ensures the restoration tissue and the healing treatments assist in this process. The objectives of this work were evaluated the healing evolution and quality of surgical wounds treated with antiseptic and open skin wounds treated with creams containing different concentrations of Triticum vulgare. The evaluated of antiseptics was realized in dogs submitted to ovariohysterectomy and treated with 10% polyvinyl-pyrrolidon iodine (PVPI), 0,5% chlorhexidine or 0,9% physiological solution, during 10 days. The evaluated of phitotherapy was realized in rabbits being studied 135 wounds at days seven, 14 and 21 and divided in groups with ten wounds of each treatment for clinical and histopathological analysis and 15 for tensiometer analysis, the treatments were realized with aqueous extract of T. vulgare in the concentration 2mg/ml and 10mg/ml and nonionic cream, during 21 days. The surgical and open wounds were analyzed as the healing quality and climical aspect in: exudate type and quantity, epithelialization and granulation tissue formation, being that in open skin wounds was added the concentration analysis. In the open skin wounds were still realized analysis histopathological, tensile breaking strength and strength tensiometer. In the surgical wounds no observed significative difference between the treatments in clinical evaluations over the studied period. Purulent exudates occurred in all the treatments during the experimental period, although in the day 10 the wound treated with 0,9% physiological solution differed from the other treatments. (p=0,0429). The wounds treated with physiological solution allowed the stitches removal within 7 days, differed from others treatments (p=0,0357). In the evaluated of healing quality the wound treated with 0,5% chlorhexidine presented more percentage of normotrophy wounds (70%) and in to the skin anatomic limits(40%). The treatment with PVPI differed of other groups because has not wound into the skin anatomic limits (p=0,0085). In the work with open skin wounds treated with different concentration of Triticum vulgare and cream nonionic was demonstrated that the clinical analysis evolution, histopathological (phases of healing process and collagen) and tensile breaking strength have not significant difference between the groups. In the strength tensiometer analysis the treatment with Triticum vulgare 2mg/ml statistically different from the control group. (p=0,0295). In the study condition concluded that there was no difference in healing of surgical wound treated with 10% polyvinyl-pyrrolidon-iodine, 0,5% chlorhexidine or 0,9% physiological solution, although the chlorhexidine has determined highest percentage of normotrophy wound and into the normal limits. Have not difference in the healing process of open wounds treated with the two concentrations of creams containing aqueous extract of Triticum vulgare and nonionic cream, but the wound treated with cream containing aqueous extract of Triticum vulgare 2mg/ml presented better results in the strength tensiometer evaluation. / O processo cicatricial compreende um dinâmico processo celular que garante a restauração tissular, os tratamentos para a cicatrização auxiliam nesse processo. Na medicina veterinária os anti-sépticos são utilizados rotineiramente para a cicatrização de feridas e atualmente os fitoterápicos têm sido bastante estudados. Os objetivos desse trabalho foram avaliar a evolução e a qualidade da cicatrização de feridas cirúrgicas tratadas com anti-sépticos e feridas cutâneas abertas tratadas com cremes contendo concentrações diferentes de Triticum vulgare. A avaliação dos anti-sépticos foi realizada em 30 fêmeas caninas submetidas à ovariosalpingohisterectomia e tratados com: polivinil-pirrolidona iodo (PVPI) 10%, clorexidine 0,5% ou solução fisiológica 0,9%, em dias alternados durante dez dias. A avaliação do fitoterapico foi realizada em coelhos, sendo estudadas 135 feridas aos dias sete, 14 e 21 e divididas em grupos de dez feridas de cada tratamento para análise clínica e histopatológica e 15 para a tensiométrica, os tratamentos utilizados foram com extrato aquoso de T. vulgare na concentração de 2mg/ml e de 10mg/ml e creme não iônico, durante 21 dias. As feridas cirúrgicas e abertas foram analisadas quanto a qualidade cicatricial e ao aspecto clínico em: tipo e quantidade de exsudato, formação do tecido de granulação e epitelização, sendo que nas feridas cutâneas abertas foi acrescentando a análise de contração. Nas feridas cutâneas abertas ainda foram realizadas análise histopatológica, força de ruptura e tensiométrica. Nas feridas cirúrgicas não foi observada diferença significativa entre os tratamentos ao longo do período estudado nas avaliação clínicas. Exsudato purulento ocorreu em todos os tratamentos durante o período experimental, embora no dia 10 as feridas tratadas com solução fisiológica 0,9% diferiram dos demais tratamentos (p=0,0429). As feridas tratadas com solução fisiológica permitiram a retirada de pontos em até sete dias, diferindo dos demais tratamentos (p=0,0357). Na avaliação da qualidade cicatricial, as feridas tratadas com clorexidine 0,5% apresentaram maior percentual de feridas normotróficas (70%) e dentro dos limites anatômicos da pele (40%). O tratamento com PVPI diferiu dos demais grupos devido não possuir feridas dentro dos limites anatômicos da pele (p=0,0085). Nas feridas cutâneas abertas tratadas com concentrações diferenciadas de T. vulgare e creme não iônico foi demonstrado que na evolução da análise clínica, histopatológica (fases do processo cicatricial e colágeno) e da força de ruptura não houve diferença significativa entre os grupos. Na análise tensiométrica o tratamento com T. vulgare 2mg/mI diferenciou-se estatisticamente do grupo controle (p=0,0295). Nas condições do estudo concluí-se que não houve diferença na cicatrização de feridas cirúrgicas tratadas com polivinil pirrolidona iodo 10%, clorexidine 0,5% e solução fisiológica 0,9%, embora o clorexidine tenha determinado maior percentual de feridas normotróficas e dentro dos limites normais. Não houve diferença no processo cicatricial de feridas abertas tratadas com os as duas concentrações de cremes contendo extrato aquoso de T. vulgare e creme não iônico, mas as feridas tratadas com o creme contendo extrato aquoso de T. vulgare 2 mg/ml apresentaram melhor resultado na avaliação tensiométrica

Dans ce travail, nous nous sommes intéressés au développement d’un nouveau biocapteur enzymatique ultrasensible pour la détection conductimétrique d’une mycotoxine, l’ochratoxine A (OTA). Une peptidase, la thermolysine (TLN), a été choisie comme élément de reconnaissance. Le biocapteur proposé est basé sur l’immobilisation de la TLN dans une matrice d’alcool polyvinylique (PVA)/polyéthylènimine (PEI) contenant des nanoparticules d’or et réticulée à la surface de microélectrodes interdigitées à l’aide de vapeurs de glutaraldéhyde. Dans les conditions optimales (35 min de réticulation, mesure à pH 7 et 25°C), la réponse du biocapteur est linéaire jusqu’à 60 nM et la limite de détection est de 1 nM. Cette valeur est 700 fois plus basse que celle obtenue en utilisant une méthode d’immobilisation basée sur la co-réticulation de la TLN en présence d’albumine de sérum bovin (BSA). La matrice PVA/PEI crée un environnement aqueux favorable à l’enzyme. Par ailleurs, les interactions entre les groupements amines protonés du PEI et les charges négatives des nanoparticules citratées et de la TLN améliore leur dispersion dans la matrice et favorise la stabilisation de l’enzyme et son accessibilité au substrat (OTA). Le biocapteur conductimétrique développé est très reproductible et stable pendant 30 jours lorsqu’il est stocké à 4°C dans du tampon phosphate 20 mM pH7 entre 2 mesures. Le biocapteur a ensuite été évalué sur des échantillons d’huile d’olive commerciale dopée. Aucun prétraitement de l’échantillon n’a été nécessaire et des taux de recouvrement proches de 100% ont été obtenus, démontrant l’absence d’effet de matrice / A new ultrasensitive enzymatic biosensor for the direct conductometric detection of ochratoxin A (OTA) has been developed in this work. Thermolysin (TLN), a peptidase, was chosen as recognition element. The proposed biosensor is based on TLN immobilization into a polyvinyl alcohol (PVA)/polyethylenimine (PEI) matrix containing gold nanoparticles (AuNPs) and cross-linked at the surface of gold interdigitated microelectrodes using glutaraldehyde vapor. Under optimal conditions (35 min cross-linking time, working pH of 7 and temperature of 25◦C), the biosensor response was linear up to 60 nM OTA and the limit of detection was 1 nM. This value was 700 times lower than the detection limit obtained using the more classical method based on enzyme cross-linking in the presence of bovine serum albumin (BSA). PVA/PEI hydrogel creates a very favorable aqueous environment for the enzyme. In addition, interactions between protonated amino groups of PEI and negative charges of both citrated AuNPs and thermolysin improve their dispersion in the polymer blend, favoring enzyme stabilization and accessibility to the substrate (OTA). The developed OTA biosensor was very reproducible and stable over a 30 days period when stored at 4◦C in 20 mM phosphate buffer between two measurements. The method was further evaluated using commercial doped olive oil samples. No pretreatment of the sample was needed for testing and no matrix effect was observed. Recovery values were close to 100%, demonstrating the suitability of the proposed method for OTA screening in olive oil

This diploma thesis investigates the suitability of relaxation tests as a part of complex characterization of hydrogel materials using classical rheology methods. With respect to the current research, creep and three interval thixotropy tests were taken into account. For them, general optimization was done aiming to find an ideal parameter settings. The optimization was performed using physically crosslinked agarose (AG) hydrogel and the tuned tests were also applied to two more samples: hyaluronan (HyA) and polyvinyl alcohol (PVAl) gel. These materials were selected due to their mutually different crosslinking principle. The experiments showed, the AG gel proved to have the best ability to recover after deformation of all studied samples. On the other hand, the HyA gel relaxed the worst. Although the final results of both tests were comparable, the regeneration process itself was different. Hence, the complex relaxation characteristics cannot be described using one of the performed tests alone and both the creep and three interval thixotropy tests have great importance in the scope of complex relaxation behaviour. The obtained results may lead to more precise description of deformation and relaxation, which are frequent phenomena occurring during treatment and application of hydrogel materials.

The subject of the thesis is to improve the moisture resistance of MDF (macro-defect-free) composites prepared on the basis of aluminous cement and polyvinyl alcohol. These materials are characterized by the absence of defects in the structure and high mechanical performance. These features make MDF composites a promising type of material that could be used in the future for construction purposes. The basic deficiency of MDF composites is insufficient resistance to water or moisture, accompanied by a significant decrease in strength. Therefore, this work deals with increasing of moisture resistance using organotitanate agent and modification of the polymer. Two types of polyvinyl alcohols differing in hydrolysis degree and degree of the polymerization has been modified. Based on the results of the measurement the effect of storage conditions on the properties and structure of prepared MDF composites was observed. The characterization of MDF composites were realized by measurement of flexural strength in bending, scanning electron microscopy with EDS analysis, TG-DTA-EGA, water absorption and consequently the porosity of all prepared MDF composites.